The program outlined herein is directed at the total synthesis of a diverse set of natural products which show biological activity as hormonal, antibiotic, or antigungal agents. The synthetic shcemes presented are designed to provide expedient and efficient access to the targeted natural products and synthons thereof in optically active form. The routes should be amenable to the production of significant quantities of the target molecules and molecular analogs for biological screening purposes. The proposal includes synthetic routes to prostanoids such as 11-deoxy PGF2Alpha (1) and PGF2alpha (2), corticosteroids such as adrenosterone (3), the "left-wing" of the ionophore antibiotic X-14547A (4), synthons 5 and 6 for the leukotriene and tricothecene natural products, respectively, and the trio of antifungal agents ethisolide (7), isoavenaciolide (8), and avenaciolide (9). All of the targeted molecules will be prepared in their correct (natural) enantiomeric configurations. These investigations will allow us to continue to develop and apply new chemistry from our laboratories relating to asymmetric synthesis, intramolecular cycloadditions, sigmatropic rearrangements, and organosilicon chemistry. In particular, we will continue to develop and apply procedures based upon the intramolecular Diels-Alder reaction (IDAR), the intramolecular ene reaction, and the Claisen rearrangement.